Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:114667
MIME-Version: 1.0
References: <f3d20496-c560-42b7-9a0d-8672b3cafa7d@www.fastmail.com> <60b2b70c.1c69fb81.dd8bc.e30aSMTPIN_ADDED_MISSING@mx.google.com>
In-Reply-To: <60b2b70c.1c69fb81.dd8bc.e30aSMTPIN_ADDED_MISSING@mx.google.com>
Reply-To: Levi Morrison <levi.morrison@datadoghq.com>
Date: Sat, 29 May 2021 20:43:50 -0600
Message-ID: <CAAKU0ukPHgvHsPc25-_17KaYFjoYqvDu2Q1wQLAi0sbOtRTsHQ@mail.gmail.com>
To: Mark Randall <marandall@php.net>
Cc: PHP internals <internals@lists.php.net>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Subject: Re: [PHP-DEV] Re: [RFC] Partial function application
From: internals@lists.php.net ("Levi Morrison via internals")

On Sat, May 29, 2021 at 3:50 PM Mark Randall <marandall@php.net> wrote:
>
> On 25/04/2021 20:25, Larry Garfield wrote:
> > It includes an implementation by Joe Watkins that is already about 95% =
complete.  (There's some edge cases he's still sorting out, but all of the =
typical cases should work already.)  Most of the design work comes from Lev=
i Morrison and Paul Crovella.  I helped out with the tests, a few edge bits=
, and general instigator/nudge. :-)
>
>
> Can I be a little pushy and ask for a subvote on "..." vs "...?"
>
> It _probably_ won't matter, but with ... being used as the language's
> universal variadic / unpack, we may use it for similar things in the
> years to come, and I think it makes sense to pre-empt a potential
> conflict or source of confusion down the line by using "...?".
>
> Just as a variadic function argument is ...$ a variadic partial closure
> would be ...?
>
> I do not, at this time, have a firm example of where this might become a
> problem, otherwise I would state it. The closest I can think of for now
> is that it's entirely possible that auto-capturing multiline functions
> may end up using:
>
> $x =3D function() use (...) { /* */ }
>
> Which could possibly be confusing. Not a definiative example by any
> stretch, but but I do get the feeling that, as we can future proof it
> for effectively zero cost, we should.
>
> Mark Randall

I do like the symmetry:

Positionals:
    f($x)  -->  f(?)
Named:
    f(x: $x)  -->  f(x: ?)
Variadic:
    f(...$args)  -->  f(...?)

You are right that it _might_ be more future compatible. I don't care
about the extra character in this case, as the char does add some
visual cue:

    $callback =3D $serializer->pack(...);
    $callback =3D $serializer->pack(...?);